JPH0629124B2 - Aluminum nitride powder manufacturing method, aluminum nitride sintered body and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing aluminum nitride, and more particularly to a method for producing aluminum nitride powder in which aluminum oxide powder contains a non-translucent element and the aluminum nitride powder. The present invention relates to a sintered body using powder and a manufacturing method thereof.

[Prior Art] Generally, when a sintered body is formed from aluminum nitride powder by a powder metallurgy method, the translucency of the sintered body increases as the thermal conductivity increases.

However, it was difficult to obtain a sintered body having uniform translucency due to easy burning unevenness and color unevenness during the manufacturing process of the sintered body. On the other hand, when a sintered body of aluminum nitride is used as the substrate of the optical semiconductor element, its translucency is I
It was known to have an adverse effect on C memory.

In order to solve this problem, W0 ₃ , MoO ₃ , TiC, etc. are added to aluminum nitride powder, and a mixed powder thereof is formed into a non-translucent sintered body by a powder metallurgy method. The method is being developed.

[Problems to be Solved by the Invention] However, in the conventional manufacturing method described above, the added W is added.
There is a possibility that elements such as O ₃ , MoO ₃ , and TiC may be precipitated in the grain boundaries together with the sintering aid, resulting in a decrease in high thermal conductivity.

Therefore, a technical object of the present invention is to add a group IVa, Va, VIa, or VIII group element to a mixture of aluminum oxide and carbon, so that the high thermal conductivity is not lowered, and the firing is non-translucent. An object of the present invention is to provide a method for producing an aluminum nitride powder capable of forming a bonded body, a sintered body using the aluminum nitride powder, and a method for producing the same.

[Means for Solving the Problems] In order to solve the problems of the above-mentioned conventional techniques, the present invention uses aluminum oxide and carbon in a molar ratio of 1: 4.
Mix in the range of 1: 6 to make the weight ratio within the range of 0.1 to 1.0 wt% with respect to aluminum nitride IV
After adding at least one of the elements a, Va, VIa and VIII, the mixture is granulated and dried to 1500 ° C.
It is characterized in that high temperature synthesis is performed in a nitrogen atmosphere at a temperature higher than 1800 ° C. and a temperature lower than 1800 ° C., and the synthesized product is heated in the air to obtain aluminum nitride used as the non-translucent sintered material powder.

In the present invention, the mixing ratio of aluminum oxide and carbon is limited to a molar ratio within the range of 1: 4 to 1: 6.
If the molar ratio is less than 1: 4 (eg, 1: 3, 1: 2, etc.), the reactivity of the mixed material is poor, and if it is greater than 1: 6 (eg, 1: 7), the workability in removing carbon is high. Is bad and leads to high cost.

Further, in the present invention, the mixture is granulated and dried, and the temperature is in the range of 1500 to 1800 ° C. in an N ₂ stream,
It is preferably 650 to 1750 ° C.

The reason is that the reaction efficiency is poor at a temperature of 1500 ° C. or lower in the synthesis in N ₂ stream, while the grain growth is remarkable at a temperature of 1800 ° C. or higher.

Further, the aluminum nitride sintered body of the present invention is a sintered body containing the colored aluminum nitride powder obtained by the above-mentioned manufacturing method, has a low light-transmitting property, and is at least 16
It is characterized by having a high thermal conductivity of 0 W / mK.

Furthermore, the manufacturing method of the aluminum nitride sintered body of the present invention comprises:
A non-translucent aluminum nitride is formed by adding a sintering aid made of a rare earth element to the colored aluminum nitride obtained by the method for producing an aluminum nitride powder, molding the mixture, and heat-sintering the mixture. It is characterized in that a sintered body is obtained.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

A manufacturing method according to an embodiment of the present invention will be described.

Example 1. Low soda alumina and carbon black 102 each
g and 48 g were mixed, and 0.13 g (0.1% by weight with respect to aluminum nitride) of Group IV Ti in the form of TiO ₂ was added to the mixture as a colorant and mixed in an organic solvent.
Next, the mixture was granulated and dried, and synthesis was performed in a nitrogen stream at 1650 ° C. for 3 hours.

In the next step, the synthetic powder was heated in air at 700 ° C. for 2 hours to remove the black carbon and produce an aluminum nitride powder. 1% by weight of Y ₂ O ₃ as a sintering aid was added to the aluminum nitride powder obtained by this manufacturing method, they were mixed and molded, and sintered by heating at 1850 ° C. in a nitrogen atmosphere to sinter aluminum nitride. Get the body. The sintered body obtained by this manufacturing method did not show translucency, but showed a high thermal conductivity of 200 W / mK.

Example 2. Low soda alumina and carbon black 10 each
2 g and 48 g were mixed, and V of Group V was mixed with V ₂
0 was added with ₅ form 0.14 g, combined to produce an aluminum nitride powder in the same manner as in Example 1 to produce a sintered body from the powder.

The sintered body did not show translucency and had a high thermal conductivity of 190 W / mK.

Example 3. Low soda alumina and carbon black 10 each
2g and 72g were mixed, and VIa was added to the mixture as a coloring agent.
The Cr families _Cr (1 wt% relative to aluminum nitride) 1.19 g in 2 _{0 3} in the form added, mixed in an organic solvent. Next, after granulating and drying the mixture, 1750 ° C
Was synthesized in a nitrogen stream for 3 hours, and the synthesized powder was heated in the air at 700 ° C. for 2 hours to remove carbon black to produce an aluminum nitride powder. With this powder,
A sintered body was manufactured in the same manner as in Example 1. The sintered body produced by this method did not show a light-transmitting property and showed a high thermal conductivity of 175 W / mK.

The high thermal conductivity of the sintered body produced by using the aluminum nitride powder obtained by the method of Examples 1 to 3 described above, and 81 g of the conventional commercially available aluminum nitride powder, Ti0 ₂ 0. 16 g or V ₂ 0 ₃ 0.17
When compared with the thermal conductivity of each sintered body obtained by adding g, mixing and molding, and sintering at 1850 ° C. in a nitrogen atmosphere, the conventional sintered body does not show translucency. Thermal conductivity is 13
It showed 0,140 W / mK.

That is, the thermal conductivity of any conventional sintered body was lower than the thermal conductivity of the sintered body manufactured using the aluminum nitride powder according to the example.

[Effects of the Invention] As described above, in the method for producing an aluminum nitride powder of the present invention, aluminum oxide and carbon are mixed in a molar ratio of 1: 4 to 1: 6, and the weight ratio of aluminum oxide to carbon is equal to that of aluminum nitride. IV within the range of 0.1 to 1.0 wt%
After adding a, Va, VIa, or VIII group element as a colorant, the mixture is granulated, dried, and synthesized at high temperature in a nitrogen atmosphere, and the mixture is heated in the air to remove carbon and nitride. By producing an aluminum powder, when a sintered body is produced by using the powder, the obtained sintered body has a high thermal conductivity of 160 W / mK or more and is excellent in that it has non-translucency. It has characteristics.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP 62-132711 (JP, A) JP 52-107299 (JP, A) JP 63-162576 (JP, A)

Claims (3)

[Claims] 1. Aluminum oxide and carbon are mixed in a molar ratio of 1: 4 to 1: 6 so that the weight ratio with respect to aluminum nitride is in the range of 0.1 to 1.0 wt% IVa. , Va, VIa, VIII, after adding at least one of the elements, the mixture is granulated and dried,
High temperature synthesis in a nitrogen atmosphere at a temperature higher than 0 ° C and lower than 1800 ° C, and heating the synthesized product in the atmosphere,
A method for producing an aluminum nitride powder, comprising obtaining aluminum nitride used as a non-translucent sintered body raw material powder. 2. A sintered body containing a colored aluminum nitride powder obtained by the manufacturing method according to claim 1, which has a high thermal conductivity of at least 160 W / mK. body. 3. A colored aluminum nitride obtained by the method for producing an aluminum nitride powder according to claim 1, further comprising a sintering aid made of a rare earth element,
A method for producing an aluminum nitride sintered body, which comprises molding, heating and sintering to obtain a non-translucent aluminum nitride sintered body.